Flexural Performance of Ultra-High Performance Concrete Ballastless Track Slabs

2016 ◽  
Author(s):  
Weina Meng ◽  
Kamal Henri Khayat
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Superior Performance ◽  
Concrete Slabs ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Cracking Behavior ◽  
Flexural Performance ◽  
Ballastless Track ◽  
Track Slab

Ballastless track slab offers excellent stability and durability and has been well accepted in high-speed railways worldwide. Rails are typically laid on precast concrete slabs that are subjected to dynamic load transferred from the rails. Cracks can be induced by shrinkage and mechanical loading in concrete, which accelerates the degradation and affects the performance of the track slab. As tens of thousands of miles of ballastless track are constructed, effective and efficient maintenance for the concrete slabs has become an issue. In this paper, ultra-high performance concrete (UHPC) is proposed to fabricate ballastless track slab. UHPC is a superior fiber-reinforced, cementitioius mortar, which has greatly-improved mechanical strengths and durability. A recently-developed UHPC is evaluated in terms of the flowability, durability, shrinkage, and mechanical properties. A functionally-graded slab design is proposed with the consideration of initial material cost. The slab is cast with two layers: a layer of conventional concrete at the bottom, and a layer of UHPC on the top. A three-dimensional finite element model is developed for ballastless track slab whose flexural performance is investigated and compared with that of slab made with conventional concrete. Concrete damage plasticity model is incorporated to consider the post-cracking behavior. The results indicate that the proposed UHPC is promising for fabricating ballastless track slab with superior performance.

scholarly journals Materials for Production of High and Ultra-High Performance Concrete: Review and Perspective of Possible Novel Materials

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4304
Author(s):  
Markssuel Teixeira Marvila ◽  
Afonso Rangel Garcez de de Azevedo ◽  
Paulo R. de de Matos ◽  
Sergio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Review Article ◽  
Cement Matrix ◽  
Bibliographic Databases ◽  
Future Research ◽  
Chemical Additives ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Essential Components

This review article proposes the identification and basic concepts of materials that might be used for the production of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). Although other reviews have addressed this topic, the present work differs by presenting relevant aspects on possible materials applied in the production of HPC and UHPC. The main innovation of this review article is to identify the perspectives for new materials that can be considered in the production of novel special concretes. After consulting different bibliographic databases, some information related to ordinary Portland cement (OPC), mineral additions, aggregates, and chemical additives used for the production of HPC and UHPC were highlighted. Relevant information on the application of synthetic and natural fibers is also highlighted in association with a cement matrix of HPC and UHPC, forming composites with properties superior to conventional concrete used in civil construction. The article also presents some relevant characteristics for the application of HPC and UHPC produced with alkali-activated cement, an alternative binder to OPC produced through the reaction between two essential components: precursors and activators. Some information about the main types of precursors, subdivided into materials rich in aluminosilicates and rich in calcium, were also highlighted. Finally, suggestions for future work related to the application of HPC and UHPC are highlighted, guiding future research on this topic.

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

scholarly journals Ground Glass Pozzolan in Conventional, High, and Ultra-High Performance Concrete

2018 ◽  
Vol 149 ◽  
pp. 01005 ◽  
Author(s):  
Arezki Tagnit-Hamou ◽  
Ablam Zidol ◽  
Nancy Soliman ◽  
Joris Deschamps ◽  
Ahmed Omran
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Ground Glass ◽  
Strengthening Effect ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Supplementary Cementitious Material ◽  
Pozzolanic Material ◽  
And Performance

Ground-glass pozzolan (G) obtained by grinding the mixed-waste glass to same fineness of cement can act as a supplementary-cementitious material (SCM), given that it is an amorphous and a pozzolanic material. The G showed promising performances in different concrete types such as conventional concrete (CC), high-performance concrete (HPC), and ultra-high performance concrete (UHPC). The current paper reports on the characteristics and performance of G in these concrete types. The use of G provides several advantages (technological, economical, and environmental). It reduces the production cost of concrete and decrease the carbon footprint of a traditional concrete structures. The rheology of fresh concrete can be improved due to the replacement of cement by non-absorptive glass particles. Strength and rigidity improvements in the concrete containing G are due to the fact that glass particles act as inclusions having a very high strength and elastic modulus that have a strengthening effect on the overall hardened matrix.

Evaluation of Flexural Performance in UHPC(Ultra High Performance Concrete) According to Placement Methods

2009 ◽  
Vol 417-418 ◽  
pp. 581-584 ◽  
Author(s):  
Gum Sung Ryu ◽  
Su Tae Kang ◽  
Jung Jun Park ◽  
Gyung Taek Koh
Keyword(s):  
Flexural Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Initial Crack ◽  
Ultra High Performance Concrete ◽  
Remarkable Feature ◽  
Flexural Performance ◽  
Placement Method ◽  
Compaction Properties ◽  
And Diffusion

Apart from its high compressive, tensile and flexural strengths reaching approximately 200MPa, 15MPa and 35MPa, respectively, Ultra High Performance Concrete (UHPC) is characterized by its high resistance against degrading factors that can delay their penetration and diffusion speeds down to 1/20 to maximum 1/10,000 compared to ordinary concrete. UHPC also exhibits self-compaction properties with a slump flow of about 220mm. Furthermore, the most remarkable feature of UHPC is the improvement of its flexural strength and toughness through the admixing of steel fiber. Accordingly, this study evaluates the effects of the placement method on the flexural performance of UHPC. As a result, the flexural strength of UHPC appears to be extremely dependent on the placement method with variation of the maximum flexural strength up to 2 to 3 times while poor influence is observed on the initial crack strength.

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